Biodegradable polymer sustained release formulations have been used to administer drugs over a prolonged period of time. See, e.g., U.S. Pat. Nos. 3,773,919 and 4,767,628. These formulations are generally in the form of solid cylindrical implants, microcapsules, or microspheres. Solid implants require incisions in the patient which often are quite painful, resulting in poor patient compliance. Solid microcapsules and microspheres, which are injected into the patient, are often difficult to reproducibly manufacture and, thus, can give varying release profiles. Also, microcapsules and microspheres require lyophilization in order to avoid agglomerization of the particles during storage and large needles for injection.